Diesel vs. Gas Mileage

MtnGuy · 03-12-2010, 09:49 AM

I kinda hijacked another thread on a new diesel F250, and thought I would start this thread to move the conversation to a more appropriate place.

Here is where I hijacked the other thread:

http://www.forestriverforums.com/for...ead.php?t=5541

Quote:

Originally Posted by MightyMike

YIKES!!! A 5.4 to that, hope you're ready for the shock at the fuel station. I really love my 6.4, it's an awesome motor for pulling heavy loads. Just can't believe the rotten fuel mileage they get. Nice truck!

Not to totally hijack Ed's thread (hey, that rhymes

), but I had always presumed that diesels got better fuel mileage than gassers, especially under load. Sounds like you have experienced both engines. Care to elaborate??

MtnGuy · 03-12-2010, 09:56 AM

And to carry over the 2 replies from the other thread:

Quote:

Originally Posted by grhodes50

Congrat's EdJunior. Enjoy that truck! Your gonna love those heated seats on cold mornings! Don't know if you had one before, but the in dash brake controller works great.

I have the same year and model as EdJunior except mine has the 5.4. Works for me since I only have a few rolling hills where I travel. Sufficient power and outstanding stabillity.

I know EdJunior will enjoy the power but I'll bet he'll get better mpg's than I do.
The best I've got is 16 mpg unloaded, 8.5 mpg towing.

Quote:

Originally Posted by Ed H

Nice truck and you'll find parking in a normal slot is interesting. I HAD a nice Ram 2500 megacab with their CTD. Loved it but wife said we need to save some money. So I traded for a gasser 2500. Talking about mileage - I get 15mpg if I'm lucky and pulling 6500 pound 831rlbss I get 7.3. With a 32 gal tank I'll be empty in some 220 miles on mostly flat lands from batesville MS to Jackson TN. And running 89 oct is the same price now as diesel. Sure wish I had my megacab back. But I'm sure you'll enjoy your 250. After the 2007 models with their particulate filters and egr valves the mileage dropped from the 20s to the teens. I found that particulate filter the killer mostly.

rockwood06 · 03-12-2010, 12:18 PM

I would like to have something cleared up from what I have been told, I hear that with the price of a truck equip with a diesel, the price of diesel fuel and the maintains that there is a long term recovery then what there is with gas engines, is this true?
I do not own a diesel, I have a 6.0 Vortec in a heavy duty 1/2 with a 4:10 rear and average 16.5 to 19.5 with out towing and around 10 towing and I am sure that will very on what part of the state I go. With my truck being a 2008 I only have 10,000 miles on it, I guess I am at the max gas mileage.

MtnGuy · 03-12-2010, 12:46 PM

Wade, I get a little better in both towing and non-towing, but not by much. I have a smaller engine (5.4) and a little stiffer gears (3.73). In the hill country that we have around here, I sometimes wonder if the lower final drives might actually help the gas mileage. That 4.10 and bigger engine will definitely help you off of the line.

Again, I am not trying to start a war here with diesel vs. gas fuel mileage. I just want to hear a viable discussion on the pros and cons so if I decide to get a new truck then I can make an informed decision on which way to go. The maintenance cost that Wade brought up is another part of that equation.

rockwood06 · 03-12-2010, 01:24 PM

I think the end result is how one drives, It may balance out. All fuel testing is done under perfect conditions and expert driving to get the best it can do for ratings. I hate to say this but no one is perfect in the real world. Most people that are on the road are gas and go drivers, no reguards to tire pressure just one little thing that can mke a differance no matter what type of engine one has.
One thing that was said to me when I sold my 3/4 ton Suburban just before we had the big snow fall, the gentleman that bought it said he knew that my vehicle was the one for him because he saw the camper in the driveway and he knows that people that RV take care of there vehicles....So I must say we RV'ers are recogized.

aintgotnun · 03-12-2010, 04:16 PM

The upfront cost of a new diesel as opposed to a gas engine is pretty high. Around $5k if I remember correctly so the return on investment is long term for a diesel. As far as better mileage goes I guess that just depends on what you tow, where you tow, and how you tow.

I got anywhere from 7.5mpg to 11mpg with my last 5'er towing at 70mph plus. With my current 5'er I get anywhere from 10 to 12.5 towing 65mph average. This is with a 2000 F350 4 door dually with the 7.3 PSD and a 4:10 rear end. Running dry I get 17.5 up to 20mpg on the highway depending on how heavy my foot is. I bought my truck used so my return on investment is about even I suppose since I now have over 145k miles on the clock.

your mileage may vary

EdJunior · 03-12-2010, 09:38 PM

Well, I can't add too much to this since I just got my diesel. With my 5.4L towing my 5500 travel trailer, I got between 8 and 11 towing (mostly fairly flat land in Texas), and between 15 and 16 mpg not towing (mostly 65mph back and forth to work). Heresay for the 6.4 is the DPF killed the decent mileage the 6.0L and 7.3L diesels got. The redid the technology in the 2011 Superduty, but the jury is still out since no one has one yet. I needed the diesel because I got a bigger trailer...and a 5th wheel to boot. We'll see how the mileage plays out.

MightyMike · 03-12-2010, 11:56 PM

Quote:

Originally Posted by mtnguy

I kinda hijacked another thread on a new diesel F250, and thought I would start this thread to move the conversation to a more appropriate place.

Here is where I hijacked the other thread:

http://www.forestriverforums.com/for...ead.php?t=5541

Not to totally hijack Ed's thread (hey, that rhymes

), but I had always presumed that diesels got better fuel mileage than gassers, especially under load. Sounds like you have experienced both engines. Care to elaborate??

Well, I guess I can chime back in. Although not exactly an apples/apples deal, I had in order, a pop-up, a 21' TT,24' TT, 29' 5er, and now a 39' Toy hauler. Towed with, 87 Bronco-302/4 spd man, 89 E150 conv. van, '00 F250 SD, sc short bed-7.3/6 spd man., and now an 08 F350 CC b DRW-6.4/auto. Towing with the gassers I usually got 7-9 mpg towing, 15-18 around home. F250 was bought specifically for 1st 5er- got around 10 towing and 15-18 at home. That 7.3 loved the cetane boost,and I once got 12 mpg (going south, downhill, right?). What I meant by my original comment was the 6.4 mileage was killed by the EPA. Guys on the truck forum post this is to be expected with a heavy truck, but I don't buy that. Big rigs have 18 whls moving 80,000 lbs, and they get as good as these new diesels, what a bunch of crap. As to the cost, I think my diesel was a $6700 option. Throw in 15 quarts every oil change, a filter that costs $20, and maint like an air filter for $115 and multiple fuel filters for another $20, it adds up. Also have to figure diesel avgs. about 0.25/gal more than gas. I'm not complaining, I needed a diesel and that's my deal. I just think people need to really consider all the pros and cons if they really need one or not. If you figure out how many miles you tow per year, sometimes they just don't make sense. But they sure can PULLLLLL..... And as for the new Ford motor, can't see how the mileage is going to improve that much. Still has to meet all of the EPA standards, plus now their getting eurea.

MightyMike · 03-13-2010, 12:28 AM

Well, DUH! Just realized I never put up my current #s.(Gotta do a little work now and then!). My 6.4 only gets about 10mpg around home. Goes anywhere from 8-10 when towing.(Yeah, I didn't believe it stayed the same, either). And putting Cetane boost in it does absolutely nothing. I absolutely love this truck, just hate the mileage deal.

Dave_Monica · 03-13-2010, 01:11 AM

Does anyone out there have a Dodge 2500 with the 6.7L Cummins? What kind of mileage does it get compared to the earlier 5.9L's?

Dave

HookupAndGo · 03-13-2010, 07:55 AM

Following up MightyMike... I initially had a 2001 Expy with the 4.6L (forget now) and used it to tow a 26' TT. Empty, 21mpg on the open road. Towing, usually about 9 mpg. We wanted a bigger TT, so traded in the 01 Expy and got a 06 Expy with the 5.4L. Towing the same 26' TT, mileage dropped a little, to about 8.75. However, I was now driving about 5 mph faster 65-70 with no problems...truck just hummed right along.

So, time for the new TT, I upgraded to a 31' (8318). Mileage dropped down to about 7.9-8.5 depending on how hard I pushed it. But, generally, the speed was about 62 mph and average was about 8.1.

Next stop, an 06 F250 SC LB with the 6.0L. On my last trip to the Keys with 2 kayaks up on the racks, running about 68-70, I saw a solid 10.5 mpg. I have towed on shorter trips and seen just under 10 mpg (9.7). Found that kinda odd... Running empty at 70 down the highway, I am seeing about 19.5.

We still have both the Expy and the F250 and do a lot of in town driving on both. Both are sitting at about 14.8mpg over hundreds of in town miles (Melbourne, FL).

Anyway, as others have pointed out, the maintenance cost of the Diesel is higher, the fuel cost is higher...

Do I need the diesel for pulling, I could get by with the Expy. But, I really really really hate the borderline power, the stopping for fuel every 180 'ish miles (every 3 hours stinks). With the diesel I can go as long as my bladder (and the kids), I can make much better time on the road, and I feel really comfortable driving it. Nothing like having to worry about staying off the pedal -- this thing really wants to run about 73 for some reason so I have to fight myself to keep it at about 67-68.

In the end, it just comes down to what is comfortable and affordable. I love this truck and really would hate to go back to gas, but in a bigger 250 class with a big hemi or properly geared 5.4L, then maybe.

Good luck

rockwood06 · 03-13-2010, 08:44 AM

Quote:

Originally Posted by mtnguy

Wade, I get a little better in both towing and non-towing, but not by much. I have a smaller engine (5.4) and a little stiffer gears (3.73). In the hill country that we have around here, I sometimes wonder if the lower final drives might actually help the gas mileage. That 4.10 and bigger engine will definitely help you off of the line.

Again, I am not trying to start a war here with diesel vs. gas fuel mileage. I just want to hear a viable discussion on the pros and cons so if I decide to get a new truck then I can make an informed decision on which way to go. The maintenance cost that Wade brought up is another part of that equation.

No war started, but this is good. I am lerning a lot from this post for the future. This brings out what the real world is do. Before I bought the 2008 gas I had look at 2500 HD diesel but I could not see spending $50,000 for a truck to pull a 7,900 lbs TT camper when I could spend $28,000 and still be with in range and still room for a little extra cargo with a gas engine. By time my camper is ready for the junkyard and decide to by a bigger and heavier camper, the technology will change on the diesels as it will on other types of engines and then I may spend the extra money on a diesel. This is just my view based on the replies so far. The thing I miss on my 1997 Suburban is the bigger fuel tank, it had a 46 gal tank but my new truck has a 26 gal tank.

MtnGuy · 03-13-2010, 09:19 AM

Like Wade said, I think there has been very good input on this thread. Seeing some real numbers between these 2 petro setups is great. Overall, it looks like the older diesels get better mileage, with the EPA regulations killing the mileage on the new diesels. The manufacturers are advertising the gassers as getting a little better mileage then a couple of years ago. I understand that for pulling power, the diesels are boss, but now no better fuel economy than gas engines, and maybe worse when empty.

Thanks to all that responded, and hopefully others will still chime in so that we can get a better overall picture on these mileages.

aintgotnun · 03-13-2010, 11:09 AM

Folks I would also like to thank everyone for their honest and thoughtful input with real numbers. And I really dig the fact that this is NOT a diesel vs. gasser war. Each have their pluses and minuses and this thread may help some on the borderline make an informed decision.

Just another reason why FRF is THE BEST DANG RV forum on the web. Our members are the tops.

rockwood06 · 03-13-2010, 11:25 AM

Quote:

Originally Posted by aintgotnun

Folks I would also like to thank everyone for their honest and thoughtful input with real numbers. And I really dig the fact that this is NOT a diesel vs. gasser war. Each have their pluses and minuses and this thread may help some on the borderline make an informed decision.

Just another reason why FRF is THE BEST DANG RV forum on the web. Our members are the tops.

Amen to that. One thing I would like to say, this a reflection of Mike (MRimmer) For attracting such a great group of members when he started this Forum, Hats off to you Sir.

acadianbob · 03-16-2010, 02:38 PM

I'll thrown in another wrinkle. The truck that I am waiting for is the F150 with the ecoboost V-6 (s/b 2011 model). Reported to be 400HP and 400+ft lbs of torque. The BEST thing is that peak torque will be available at about 1,700 RPM; right where you need it for towing; very diesel-like; compare that to about 3,500 RPM torque peak for many current gassers. Cost (reported to be $1000) is way less that a diesel, fuel costs less, mileage is reported to be up 20% (as high as 23mpg highway). For many of us, I think this will be a clear winner. Unless you have a large 5er where even more torque and load capacity is needed, this combination seems very persuasive to me; especially if you consider the ride and handling negatives of the Heavy Duties. Don't start flaming if you have a HD diesel; I'm not knocking your pride and joy. They are very capable but you have to admit that there is some downside. All I'm saying is that there are some very interesting new gas powertrains coming along that will be game changers. There will be big advantages without going all the way to a bigger truck and a diesel.

acadianbob · 03-16-2010, 08:36 PM

Another benefit to turbo's (ecoboost) is that they perform better in high altitude situations compared to naturally aspirated. So, if you go to the mountains frequently, it is a benefit.

Greenshield · 03-22-2010, 06:29 PM

I was using a 2006 FX4 crew to tow a Rock 8317rkss Reese Dual Cam and was white knuckle, slow and right on the edge of capabilities. I was looking to get the new F-150 w/ new 400 HP and Heavy Duty Tow Package. Price was going to be steep and have read that for many trips towing, gassers ware out fast plus wheel base was short for my trailer.. I did some looking and found a used 2008 Crew F-250 Lariat with 6.4 diesel with 25,000 miles, flawless and full maintenance records( plus talked to the former owner whom is local). I got it for 28,000 OTD after some negotiating, made 3000 on the trade in equity that I then put on the Lariat. I just had my first tow with it and it was night and day. I have full warranty still and got 17 MPG on flat land. I am very please to have made the purchase thus far and I am aware of the maintenance costs, so I bought a maintenance package from dealer for 550 lifetime care, again much negotiating. Got Diesel for 2.95/gallon at Exxon in my town, 17 cents more than 87 octane and I get better mileage. Did I mention my monthly payments are 20$ less a month? Now is a great time to buy a used Diesel TV, I suggest used as the new ones are way too expensive to justify. The sense of security and lack of worry and added room for my family of five is well worth it!

Round Mound of Sound · 03-22-2010, 09:43 PM

I bought Chev 2500 6.6 diesel and get 18-19 mpg when I keep my foot out of it.
On flat land I get 13 ot 14 mpg, in big hills 8 to 12 mph. I did not buy it for fuel economy,I bougth it for power, and durability. If I was worried 1 or 2 mpg more or less I wouldn't have a TT. With this pick-up I go where I want when I want. I had a gasses and did't like running at 4000-4500 rpm on small hills in Kansas flat land.

NWJeeper · 03-22-2010, 10:00 PM

I wished the automakers would give us a smaller diesel rig. I would really like to have something the size of our '94 Toyota with a 4 cyl, turbo diesel for hauling my boat. I know they have them in other countries but we can't have them here. I don't need a huge truck, my boat is only 3700lbs. I also really appreciate the nimble ability of our Jeep Liberty at the tighter boat launches for maneuverability (another reason I don't want a huge truck). I think a smaller truck with towing capacity of 6000lbs or less and a smaller diesel engine that would get good mileage might be a great seller here.

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